Golf club

ABSTRACT

A golf club includes a club head having a face surface for hitting a ball. A center of gravity of the club head is situated on a vertical plain including an axis of a shaft. The club head includes a body portion for connecting to the shaft and a face portion attached to the body portion. The face portion is configured so that a face angle of the club head becomes a hook face.

TECHNICAL FIELD

The present invention relates to a golf club of so-called wood type, partially including a driver, a fairway wood and a hybrid club.

BACKGROUND OF THE INVENTION

Golf is one of sports played by hitting a ball with a tool. In this regard, golf is similar with baseball, tennis, badminton and so on. In spite of hitting the ball which is not moving, many golf players in an average level have a low rate of contented shots and take bad shots many times even in a situation which is not too difficult. For one of reasons of the bad shots, a club head of a golf club cannot be provided on an extension line of a linear structure from a grip, which transmits a force of a swing, through a shaft because of a regulation about the golf club except some putters.

In these days, the club head, especially of a driver, becomes larger, having a larger inertia moment around an axis of the shaft and a center of gravity situated deeper. In the golf club having such large club head, it is preferred to reduce the motion of opening and closing the club face during the swing. However, it is natural for a human body to open a face during a take back, and to gradually close the face during a forward swing. In particular, in an iron shot, it is often said that opening and closing the face is important in order to transmit the force to the ball effectively.

Further, it is said that the large club head causes less of losing initial speed of the ball or less of a curved trajectory of the ball (so-called slice and hook), even though an impact point on the face is slightly out of an ideal area. On the other hand, when the club head is opened during the take back, it is often causes a pushing since the club head is not returned to a square enough before the impact.

This is not because of the forward swing. When a player moves as opening the club head during the take back (originally it is a natural movement), in an early stage of the forward swing (pulling back the grip to the player and the shaft has a longitudinal position as being viewed from front side of the player), a line connecting a heel and a toe of the club head becomes an almost vertical direction. As a result, a strong force by gravity and a swinging force (a force in the almost vertical direction) is applied in a direction toward opening the face.

As a reaction to the opening head described above, a golfer is asked to move so as to close the face during the forward swing. To turn over arms stronger (faster) is one of the movements, though this sometimes causes the impact made with the face which is too closed. On the other hand, it is highly likely for the player to control acceleration of speed during the forward swing involuntarily, so that the head is returned to the square before the impact, resulting in head speed slower than expected.

Patent Reference 1 (Japanese Patent Publication 8-33742) discloses a conventional golf club such as the driver, resolving difficulty of swing of a conventional wood club described above and being capable of hitting the ball correctly with the club head thereof. The wood club of the Patent Reference 1 has the center of gravity of the club head on a vertical plain including the axis of the shaft so as to swing easily, and to strike the ball easily. Further, the player is drawn from where the center of gravity is situated in a draw through, thereby enabling the player to make the stable follow through.

CITATION LIST Patent Literature

Patent Reference 1: Japanese Patent Publication No. 8-33742

SUMMARY OF THE INVENTION Problem to be Solved

However, in the conventional golf club in Patent Reference 1, the center of gravity of the club head is situated on or a front side of an extending line of the shaft. In such configuration described above, the shaft keeps a virtually linear shape or slightly bows at the impact during the swing. Therefore, the face changes a facing direction thereof due to the impact. Accordingly, a direction in which the ball is hit becomes unstable. Therefore, it is necessary to adjust the swing. As a result, the conventional golf club has unstable behavior and low operability.

In view of the problem described above, an object of the present invention is to provide a golf club being capable of behaving stably during the swing and being easy to operate for general golfers in all levels.

BRIEF DESCRIPTION OF THE INVENTION

In order to attain the object described above, the present invention provides a golf club with a configuration described below.

According to a first aspect of the present invention, a golf club includes a club head having an impact surface formed in a front surface thereof. A center of gravity of the club head is situated on a vertical plain which includes an axis of a shaft. The club head includes a head main body portion for connecting to the shaft and a face portion for attaching to the head main body portion.

The face portion is configured so that a face angle thereof is a hook face of 5° to 15°.

According to a second aspect of the present invention, the golf club according to the first aspect of the present invention further includes the head main body portion and the shaft connected to each other in a middle portion in a front-back direction of the club main body portion.

Advantageous Effect of the Invention

A golf club according to an embodiment of the present invention has zero gravity depth. Therefore, at an impact, in other words, when a shaft faces toward a lower direction, the shaft 3 returns to the virtually linear shape. Therefore, a surface of the face returns to an original position. It is possible to avoid the open face caused by the impact with the ball, by making the face angle be the hook face. Accordingly, it is possible to increase smash factor since the golf club behaves stably during the swing and reproductivity of the swing is improved. In addition, though an inertia moment around an axis of the shaft is decreased, operability, such as opening and closing the face, is improved. It is also easy to choose a fade or a draw as intended.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a configuration of a golf club according to an embodiment of the present invention;

FIG. 2 is a plan view showing the golf club in FIG. 1;

FIG. 3 is a front view showing the golf club in FIG. 1; and

FIG. 4 is an explosive perspective view showing the golf club in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing a configuration of a golf club according to an embodiment of the present invention. FIG. 2 is a plan view showing the golf club in FIG. 1. FIG. 3 is a front view showing the golf club in FIG. 1 and FIG. 4 is an explosive perspective view showing the golf club in FIG. 1. As shown in FIGS. 1 to 4, the golf club 1 according to the embodiment includes a club head 2, a shaft 3 and a grip (not shown).

The club head 2 in the embodiment is a golf club head with a hollow shape, formed by joining plurality of members. The club head 2 is configured to have a length L being no more than 127 mm, and a height H being no more than 71.1 mm. The club head 2 of the embodiment is configured by joining three configuration portions; the head main body portion 10 (a first configuration portion) including a neck portion 11 to which the shaft 3 is connected, a face portion 20 (a second configuration portion) including a face surface 21 and a back face portion 30 (a third configuration portion).

The first configuration portion or the head main portion 10 of the club head 2 according to the embodiment has a tubular shape including a toe portion 12, a sole portion 13, a crown portion 14 and a heel portion 15. The head main portion 10 is made by casing a titanium alloy, for example, a 6-4 Ti alloy (Ti-6Al-4V). The face portion 20 and the back face portion 30 are provided on openings 17 opened in end surfaces 16 situated in a front and rear, and forming the club head 2 with the hollow portion.

As shown in FIG. 4, a thickness of the head main body portion 10 may be as thick as being capable of standing against a shock as the golf club 2 strikes a golf ball and not limited specifically.

As shown in FIGS. 1 and 3, the sole portion 13 has a curved shape convexing outward, corresponding to a bottom surface of a golf club head of wood type. A thickness of the sole portion 13 may be as thick as being capable of standing against the shock as the golf club 2 strikes the golf ball and not limited specifically. Typically, it is preferable that the thickness of the sole portion 13 is set between 1.0 mm to 4.0 mm. In addition, as described later, the sole portion 13 may have a portion formed to be thinner.

The sole portion 13, the toe portion 12 and the heel portion 15 configuring the head main body portion 10 may be configured as separated components from the crown portion 14. For example, the sole portion 13, the toe portion 12 and the heel portion 15 may be formed by stamping after trimming a sheet of Ti or Ti alloy into a shape of an expansion plan thereof. Then it is possible to unify the head main body portion 10 by welding the crown portion 14 at a border thereof to the crown portion 14.

The neck portion 11 is provided on substantially middle of the crown portion 14, which configures an upper surface of the head main body portion. The neck portion 11 is positioned so that a center of gravity G of the club head 2 is situated in a vertical plane including a shaft axis A (a shaft axis plane F). Accordingly, the club head 2 in the embodiment has a basic concept for the configuration thereof to have zero gravity depth. However, upon determining a detailed configuration, it is possible to have an allowance in a certain extent, considering compatibility with the ball to be used, an intended trajectory, production error and so on. For example, a distance from the vertical plane including the shaft axis A (the shaft axis plane F) to the center of gravity of the club head may be about 8 mm.

The center of gravity G of the club head 2 varies depending on, not only the configuration of the head main portion 10 but also respective configurations of the face portion 20 and the back face portion 30. Therefore, it is necessary to consider the configuration of the club head 2 as a whole. In the embodiment, the center of gravity is configured to be situated in a central portion in the front-back direction of the head main body portion 2. Further, the neck portion 11 is provided in a middle portion of the head main body portion 2. With the configuration of the head main body portion 2 described above, it is possible to utilize one head main body portion for both of right handed and left handed golf clubs. As a result, it is possible to reduce a number of components.

For the best example, commonly, in a driver or a fairway wood having the gravity depth larger than other clubs, it is possible to have the zero gravity depth as being symmetrical about a plane including a center line of the shaft and being perpendicular to a projected trajectory. In this regard, it is necessary that the back face portion 30 has a curved surface unsuitable for a striking surface and so on, because that the club head 2 is regulated to have only one striking surface.

The face portion 20 is formed, for example, as the sheet of Ti alloy and the like is trimmed along an edge of the head main body portion 10 to provide a face member in a shape of a sheet, followed by being attached by welding to a front-surface side of the end surface 16 of the head main body portion 10, so as to cover the opening 17 of the head main body portion 10.

The face portion 20 configures an outer shell of the club head 2 as being unified with the crown portion 14, the toe portion 12, the sole portion 12 and the heel portion 15, which are situated around circumference of the face surface 21.

A thickness of the face portion 20 may be as thick as being capable of standing against the shock of striking the golf ball and not limited specifically. Typically, it is preferable that the thickness of the face portion 20 is set between 2.0 mm to 4.0 mm, as taking Ti alloy for an example.

The face surface of the face portion 20 is configured so that a face angle of the club head 2 becomes a hook face. Though it is not possible to be determined uniformly due to hardness of the shaft and swinging manner of each player, for example, the face angle θ is set between 3° to 15°, preferably 5° to 10°.

The back face portion 30 is formed, for example, as the sheet of Ti alloy and the like is trimmed along the edge of the head main body portion 10 into a shape of a sheet, followed by being attached by welding to a rear-surface side of the end surface 16 of the head main body portion 10, so as to cover the opening 17 of the head main body portion 10.

The back face portion 30 configures the outer shell of the club head 2 as being unified with the crown portion 14, the toe portion 12, the sole portion 12 and the heel portion 15, which are situated around circumference of the face surface 21. In this regard, as described above, the back face portion 30 which is situated at rear of the club head 2 has the surface curved being unsuitable for the striking surface.

A thickness of the back face portion 30 may be as thick as being capable of standing against the shock of striking the golf ball and not limited specifically. Typically, it is preferable that the thickness of the face portion 20 is set between 1.0 mm to 3.0 mm. In addition, it is preferable that the back face portion 30 is configured to weigh nearly the same with the face portion 20 so that the center of gravity is situated in the central portion of the club head.

Next, movement of the club head 2 when the golf club according to the embodiment is swung will be explained. The shaft 3 is bent before and after the impact, thereby increasing the head speed with a movement to restore a shape thereof. Accordingly, upon starting to swing, the shaft is bent toward the rear direction and the club head 2 moves behind compare to the shaft. The golf club according to the embodiment has the zero gravity depth. Therefore, at the impact, that is, in a position where the shaft faces below, the shaft 3 is restored into a virtually linear shape.

When the club head 2 receives a striking force as hitting the ball, the club head 2 faces an open side of the face, being referred to be likely to cause a push shot, since the center of gravity G is situated in a toe side relative to the shaft 3. However, in the embodiment, the face angle is configured to be the hook face. Therefore, the face surface becomes square at the impact, thereby reducing the push shot.

As explained above, the golf club 1 according to the embodiment behaves in a stable manner. Therefore, when a long carry distance is desired, it is possible to apply the shaft which is lighter and longer than usual. In this case, as described below, it enables the head speed to be increased when the head weights averagely.

In the golf club 1 according to the embodiment, the shaft thereof becomes virtually linear just before the impact. Therefore, the head transmits the shaft relatively less load. As a result, it is possible to have a necessary strength even when the shaft is lighter than usual, thereby it is possible that the golf club weighs lighter as a whole. Accordingly, in general, when the length of the shaft is the same, the head speed becomes faster.

In addition, when the golf club is able to be swung in a certain pace, it is possible to increase the head speed as the shaft becomes longer. Further, the shaft which is relatively lighter and longer is bent by a relatively large amount when a flex is the same. Thereby enabling the head speed to be increased since it enables to increase a distance for accelerating the head enough to redeem disadvantage of the longer shaft during the forward swing.

Further, the head behaves in a stable manner during the swing. Therefore it is possible to swing without reducing the acceleration in the forward swing. Accordingly, it is plausible to increase the head speed.

As explained above, the golf club 1 according to the embodiment behaves stably during the swing, thereby improving reproductivity of the swing. It is also possible to increase smash factor. In addition, though an inertia moment around the axis of the shaft is decreased, operability, such as opening and closing the face, is improved. It is also easy to choose a fade or a draw as intended.

Further, when the body portion of the club head is bilaterally symmetrical, it is possible to share the component with a left handed golf club. When the face portion 20 and the back face portion 30 are bilaterally symmetrical, it is also possible to share the component with the left handed golf club. Upon attainment, it is possible to reduce production cost as well as enabling to provide the same product for left handed players almost at the same time.

The present invention is not limited to the embodiment described above and able to be embodied in various embodiments. For example, in the embodiment, the club head is configured with the body portion, the face portion, and the back face portion. The main body portion may include the back face and the club head may be configured with two components, that is, the body portion and the face portion.

The disclosure of Japanese Patent Application No. 2012-136620 filed on Jun. 18, 2012, is incorporated in the application by reference.

While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.

DESCRIPTION OF REFERENCE NUMERALS

-   1 golf club -   2 club head -   3 shaft -   10 club main body portion -   11 neck portion -   12 toe portion -   13 sole portion -   14 crown portion -   15 heel portion -   20 face portion -   21 face surface -   30 back face portion 

What is claimed is:
 1. A golf club comprising: a club head having a face surface for hitting a ball on a front surface thereof; and a shaft attached to the club head so that a center of gravity of the club head is situated on a vertical plain including an axis of the shaft, wherein said club head includes a body portion connected to the shaft and a face portion attached to the body portion, and said face portion is configured so that a face angle of the club head becomes a hook face between 5° and 15°.
 2. The golf club according to claim 1, wherein said shaft is connected to the body portion at a middle portion of the body portion in a front-rear direction thereof. 